(*#* **Example of a group: $\langle$#⟨#[Qpos],$(x,y) \mapsto xy/2$ #(x,y) ↦ xy/2#$\rangle$#⟩#
The positive rationals form with the operation $(x,y) \mapsto xy/2$
#(x,y) ↦ xy/2# a CGroup.
*)
(*#* **Example of a group: $\langle$#⟨#[Qpos],$(x,y) \mapsto xy/2$ #(x,y) ↦ xy/2#$\rangle$#⟩#
The positive rationals form with the operation $(x,y) \mapsto xy/2$
#(x,y) ↦ xy/2# a CGroup.
*)